We failed to do this before the 1.1 release, so that went out
still marked at 1.1 beta. The plan was to get rid of this file
but it's still used as a fallback by the msvc build.

commit 77880655f652c54415e4b5f03b5984b951f5267b
Author: Timothy B. Terriberry <tterribe@xiph.org>
Date:   Wed Jun 26 12:23:53 2013 +0200

    Fix version.mk parsing in genversion.bat.

    This was broken by the changes in 0482c82f to make it work with spaces.

    CMD interprets the quotes to mean the argument to FOR is a string,
    not a file name. Instead, we expand the path to a short file name.

Signed-off-by: Gian-Carlo Pascutto <gcp@sjeng.org>

commit 8e97847ecac3a04956747b117fefef14939cbcbe
Merge: 0482c82 3c0aa8fc
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Wed Jun 26 12:19:41 2013 +0200

    Merge branch 'master' into msvc_reorg

commit 0482c82fea6dd397a7d2ab50dc6cda4965278fc2
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Tue May 21 17:59:30 2013 +0200

    Make genversion.bat work in paths with spaces.

commit 3648ec55b7511119735280fc49bc57c7a3b55d6a
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Tue May 21 17:42:14 2013 +0200

    Rework output & intermediate dirs for parallel build support.

commit c367a0fcfcbf5551fb65d61365d9b832d7af2b38
Merge: bafb1dd b518b56f
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Tue May 21 14:17:11 2013 +0200

    Merge branch 'master' into msvc_reorg

    Conflicts:
    	win32/VS2010/celt.vcxproj
    	win32/VS2010/opus.vcxproj
    	win32/VS2010/silk_common.vcxproj
    	win32/VS2010/silk_float.vcxproj

commit bafb1dda3fcf6785decdfb42a1f934c7fab0c567
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Mon Mar 11 21:25:28 2013 +0100

    Fix two more files to not have the Platform Toolset explicitly set.

commit c69c870201fec7461862fe79731a37866a1810f1
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Mon Mar 11 21:08:00 2013 +0100

    Add missing SILK MSVC project files.

commit a0d41fb7f97558c8f812d500b9027c77907c37c0
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Fri Mar 8 15:00:51 2013 +0100

    Use the default toolset in the MSVC project files.

commit 34aac5b2637ed38c5620f0d876e08db232849933
Author: Gian-Carlo Pascutto <gcp@sjeng.org>
Date:   Fri Mar 8 14:54:41 2013 +0100

    Move the MSVC project files outside the source tree.

    Bring the project structure more in line with the one in libogg.

Naive builders, particular on Windows without git installed,
would get builds calling themselves 1.0.1 even though master
has diverged significantly from the 1.0.x series at this point.

We should update this file both before and after release.

Previously we defined the release version string in configure.ac,
and overrode that with 'git describe --tags' if possible. This
made it difficult for non-autoconf builds to set their version
string correctly.

Instead we create, and check into version control, a file called
version.mk which defines OPUS_VERSION. The configure script reads
that file and uses it as a fallback if the git revision isn't available.

The expectation is that version.mk will be manually updated for
releases, just as the previous configure.ac version was. However,
since this is a simpler format, it is easier for alternate build
systems to use, reducing the number of places which must be updated.

Also removes the OPUS_MINOR_VERSION, etc. defines from config.h.